Mosby Chap 3 Q 1-73

Front 1

In many cases, digital fluoroscopy eliminates which of the following?

Back 1

Postprocedure "overhead" films

Front 2

A photostimulable phosphor is the active component of what piece of equipment?

Back 2

Computed radiography imaging plate

Front 3

In computed radiography, the image plate must be turned into digital form by what device?

Back 3

Analog-to-digital converter

Front 4

A mathematical formula used to reconstruct the image in digital imaging is called?

Back 4

An algorithm

Front 5

Picture elements in a digital image are called?

Back 5

Pixels

Front 6

A digital image is composed of rows and colums known as:

Back 6

Matrix

Front 7

Direct digital radiography differs from computed radiography in what way?

Back 7

The use of fixed detectors that communicate directly with the computer

Front 8

Window width in computed radiography and digital radiography controls what image property?

Back 8

Contrast

Front 9

A graphic display that is constructed to show the radiographer the distribution of pixel values is called:

Back 9

A histogram

Front 10

The law stating that the outer shell of an atom can contain no more than eight electrons is called:

Back 10

Octet rule

Front 11

Examples of particulate radiation are:

Back 11

Helium nuclei and beta particles

Front 12

Elextromagnetic radiation travels:

Back 12

In waves along a straight path

Front 13

Electromagnetic radiation travels in bundles of energy called:

Back 13

Photons

Front 14

X-rays travels at what speed?

Back 14

The speed of light, 186,000 miles per second

Front 15

Waves of radiation are called:

Back 15

sine waves

Front 16

Wavelenght is defined as the distance from:

Back 16

Peak to peak of the wave

Front 17

Frequency is defined as:

Back 17

The number of waves passing a point per unit time

Front 18

The speed of x-rays is based on:

Back 18

The fact that they are a form of electromagnetic radiation.

Front 19

Wavelength and frequency are:

Back 19

Inversely proportional to each other

Front 20

The x-ray beam will change as it travels through the patient by a process called:

Back 20

Attenuation

Front 21

The intensity of radiation is inversely proportional to the square of the distance between the source of radiation and the person receiving it. This describes:

Back 21

Inverse square law

Front 22

As radiation strikes matter:

Back 22

The energy is transferred to the atoms according to the law of conservation of energy

Front 23

Which statements are true regarding electrostatic charges?

Back 23

Electrostatics is the study of electric charges at rest; Electrostatic charges concentrate on a conductor in the area of the greatest curvature.

Front 24

Which statements are false?

Back 24

The volt is the unit of electric current; The ampere is the unit of eletromotive force; Ohm'law is calculated using the equation VI=R

Front 25

Electromagnetic induction is the process of causing an electric to flow in a conductor:

Back 25

When it is placed in the magnetic field of another conductor

Front 26

The two types of electromagnetic induction are:

Back 26

Self- induction and mutual induction

Front 27

Self-induction is used in the operation of what device?

Back 27

autotranformer

Front 28

The strength of the magnetic fields in a transformer is increased by:

Back 28

coiling the wires and letting their magnetic fields overlap

Front 29

Electricity is supplied to the imaging department by a:

Back 29

generator

Front 30

The electricity provided to the radiology department is:

Back 30

60 Hz Ac

Front 31

The electricity provided to the radiology department operates at:

Back 31

120 pulses per second

Front 32

High-frequency power:

Back 32

Has almost no ripple

Front 33

The primary advantage of three-phase power is that:

Back 33

Voltage never drops to zero

Front 34

A variable transformer that is used to select kVp for the xray circuit is the:

Back 34

autotransformer

Front 35

A transformer that has more turns in the seconday than in the primary coil is called a?

Back 35

step-up transformer

Front 36

The transformer used to boost voltage to kilovoltage levels is called a?

Back 36

Step-up transformer

Front 37

Voltage coming to the xray machine is kept constant through the use of a:

Back 37

Line voltage compensator

Front 38

A step-down transformer:

Back 38

Steps down voltage

Front 39

Where does thermionic emission occur?

Back 39

Cathode

Front 40

What device is prereading?

Back 40

kVp meter

Front 41

What device reduces voltage and provides current to produce an electron cloud or space charge at the filament?

Back 41

Step-down transformer

Front 42

What device is electronic, with increments as low as 0.001 second?

Back 42

timer

Front 43

What changes AC to Dc?

Back 43

rectifier

Front 44

What is surrounded by a negatively chagred focusing cup?

Back 44

filament

Front 45

What is composed of solid-state, silicon-based diodes?

Back 45

Rectifier

Front 46

What regulates the duration of xray production?

Back 46

Timer

Front 47

What is located in the xray circuit between the high-voltage transformer and the xray tube?

Back 47

rectifier

Front 48

What measures tube current?

Back 48

mA meter

Front 49

What device spins at 3300 to 10,00 rpm?

Back 49

Anode

Front 50

What device uses maximum heat storage ability of the tube to deliver mAs?

Back 50

Falling load generator

Front 51

What is the source of bremsstrahlung and characteristic rays?

Back 51

anode

Front 52

What device increases voltage approximately 500 times?

Back 52

Step-up transformer

Front 53

What is the most commonly used AEC?

Back 53

Ionization chamber

Front 54

What device always delivers the shorest exposure time possible?

Back 54

falling load generator

Front 55

What device is turned by a rotor?

Back 55

anode

Front 56

Which of the following is located between the patient and the IR?

Back 56

Ionization chamber

Front 57

The filament is kept warm by:

Back 57

A standby current from the time the xray machine is turned on.

Front 58

Activating the rotor will?

Back 58

Reduce tube life

Front 59

When making an exposure, the radiographer should:

Back 59

Activate the rotor and the exposure switch in continuous motion.

Front 60

The process of thermionic emission causes:

Back 60

Electrons to boil off the filament

Front 61

The electron stream passes from cathode to anode because of____ passing through the xray tube.

Back 61

Current

Front 62

Heat is produced in the xray tube as:

Back 62

Electrons interect with the target material

Front 63

Most of the energy conversion in the xray tube produces:

Back 63

Heat

Front 64

Xrays are produced as incident electrons interect with target atoms by a process called:

Back 64

Bremsstrahlung

Front 65

Xrays are produced as incident electrons interact with inner shell electrons in target atoms by a process called:

Back 65

Characteristic

Front 66

What percentage of energy in the xray tube is converted to xrays?

Back 66

1%

Front 67

Which are properties of xrays?

Back 67

Affect film emulsion; Scatter and produce secondary radiation; Invisible to the human eye; Travel in bundles of energy called photons; can ionize matter and gases; Cause phosphors to fluoresce.

Front 68

The xray beam is:

Back 68

Heterogeneous or polyenergetic, consisting of many different energies(wavelengths).

Front 69

The xray emission spectrum consists of:

Back 69

Discrete spectrum (produced by characteristic rays) and continuous spectrum (produced by brems rays).

Front 70

The primary purpose of filtration is:

Back 70

Radiation protection

Front 71

The amount of material needed to reduce the intensity of the beam by 1/10 is called?

Back 71

Tenth-value layer

Front 72

Which statements regarding filtration is true?

Back 72

Total filtration (not less than 2.5 aluminum equivalent) = inherent filtration(glass envelope,tube housing, oil) + added filtration (aluminum).

Front 73

Calculating heat units for three-phase, twelve-pulse equipment requires the use of___ as a constant; calculating heat units for single-phase equipment requires the use of ___ as a constant; calculating heat units for three-phase, six-pulse equipment requires the use of ___ as a constant.

Back 73

1.41, 1, 1.35, because average photon energy is different with each tyoe of equipment.